Protocols
The OBD-II standard allows for five different signalling (or data) protocols to be transmitted through the OBD-II interface. These are:

SAE J1850

PWM SAE J1850

VPW ISO 9141-2

ISO 14230 KWP2000

ISO 15765 CAN

OBD-II Scan Tools
Most modern scan tools are capable of reading the 5 different data protocols. Most are capable of resetting/clearing fault codes while more advanced tools are capable of setting ECU parameters, controlling other on board units such as ABS and Air Bags as well as real time monitoring and data logging of various engine parameters.